Miracle-Gro Expand 'n Gro concentrated planting mix gives beautiful, thriving plants in containers or in the ground. Just add water and the 0.33 cu. ft. mix expands up to 3 times, nearly 1 cu. ft. When used in the ground, Expand 'n Gro loosens and aerates native soil for better plant growth. Its all-natural fibers help control moisture by holding 50% more water than basic potting soil and releasing it as plants need it. Feeds plants for up to 6 months. Size: 0.33 cu. ft.